Discard occurrences with unverified identificationVerificationStatus

[damianooldoni]

Based on issue trias-project/indicators#84:

1. Add column identificationVerificationStatus to the cols_to_use (https://github.com/trias-project/occ-cube-alien/blob/master/src/belgium/2_create_db.Rmd#L183-L193)
2. Discard occurrences with identificationVerificationStatus = "unverified". This is very similar to what we already do for occurrenceStatus (https://github.com/trias-project/occ-cube-alien/blob/master/src/belgium/2_create_db.Rmd#L234-L241)

Apply these changes in both pipelines (BE and modelling taxa at EU level).

[damianooldoni]

As mentioned by @amyjsdavis in trias-project/indicators#84 (comment) we have more values of field identificationVerificationStatus to filter out. While making the European occurrence cube I found observations with the following values:

• unverified,
• unvalidated,
• not able to validate
• control could not be conclusive due to insufficient knowledge

After briefing with @amyjsdavis, we decided to remove them.

[damianooldoni]

While making occurrence cube for risk assessment species as defined in references/modelling_species.tsv, I found some other suspect values which I think we should include in the list of values to discard:

• Unconfirmed
• Unconfirmed - not reviewed
• Unconfirmed - plausible
• Validation requested

@qgroom, @amyjsdavis: what do you think about it?

[qgroom]

I would certainly include "Unconfirmed - plausible"

I would perhaps exclude the others. There are better ways to make this decision, but they are not so straightforward.

[damianooldoni]

Thanks @qgroom. Yes, Unconfirmed - plausible can be left. I agree.

Up to now it seems this field is free: it would be much better with a specific dictionary. For example, unverified and unconfirmed, I think could be surely merged.

[damianooldoni]

Done. I will close this issue again until new values to discard will be found.